Some aphid species have appeared a month earlier than forecast and whitefly have already been spotted on overwintered brassica crops.
Growers have been advised to step up vigilance and be ready to take action to protect produce quality.
Last summer, as in 2009, whitefly numbers reached epidemic levels in Lincolnshire. UAP agronomist Dan Hayes saw infestations begin in late May to early June; about a month earlier than usual and has already started to see adults laying eggs in overwintered crops.
The Rothamsted Insect Survey has already recorded first catches of peach-potato aphids at the Starcross, Wye, Silwood Park, Broom’s Barn and Writtle trap sites and Hayes has found the first in Lincolnshire crops.
Hayes added: “These are a month earlier than forecast so the effects of the cold winter may have been outweighed by the warm dry spring.”
Where crops face pressure from either or both of these sucking pests he advises control programmes based on Movento (spirotetramat). He has found its two-way systemicity to be highly effective against these pests which hide in the growing points of brassicas or are concealed by the canopy. “Timing is key though and you need to deploy the two permitted sprays for best effect according to the main target,” said Hayes.
He added: “Marketable yield of Brussels sprouts was vastly improved. Button quality was saved from contamination and they were bigger too. It also made harvesting much more operator friendly as there weren’t any clouds of whitefly coming off crops.”
No comments yet